Go Diego Go Underwater Mystery Take a submarine adventure into compound words. Discover sea animal facts and Spanish vocabulary with Diego This Read on Your Own book helps develop essential reading comprehension skills by using more complex sentences and advanced vocabulary words. Children can earn online rewards and parents can connect the device to the online LeapFrog Learning Path to see what their child is playing and learning. For use with the LeapReader and Tag Reader pen only. LeapReader or Tag Reader pen is required and sold separately